JP6521225B2 - Transport weighing device - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a transport measuring device which weighs articles transported at intervals while transporting them.

  A transport weighing device of this type, for example, a weight sorter, weighs the articles while transporting the articles at intervals by the weighing conveyor, and sorts the articles downstream of the weighing conveyor according to the weight of the weighed articles. Sort out.

  FIG. 11 is a schematic view showing the vicinity of a weighing conveyor of such a weight sorting machine. As shown in FIG. 11A, the article G is fed from the infeed conveyor 6 to the weighing conveyor 7 supported by the load sensor 10, the weight of the article G is measured by the weighing conveyor 7, and the delivery conveyor is carried out. It is carried out to 8 and distributed according to the weight of the article G by a distribution device (not shown).

  In the weight sorter, the zero point weight value of the weighing conveyor 7 due to the change of the ambient temperature and humidity, and the increase of the deposit on the weighing conveyor 7, etc., that is, no articles exist on the weighing conveyor 7. In the unloaded state, the weight measurement value fluctuates little by little to a non-negligible size as the operation time of the weight sorting machine passes, so-called zero fluctuation occurs.

  Therefore, in order to measure the weight of the article with high accuracy, it is necessary to correct the zero point fluctuation by performing the zero point adjustment, and in order to perform the zero point adjustment, no load is present on the weighing conveyor 7. It is necessary to measure the zero weight value which is the weight value of the condition.

  Regarding the conveyance interval between the preceding article G and the subsequent article G, as shown in FIG. 11 (b), for every weighing of the articles G, the interval until the articles G do not exist in the weighing conveyor 7 at all times. The prospect of tp is often difficult to realize in a weight sorter provided in the subsequent transfer line of a high production apparatus.

  For this reason, in Patent Document 1, the low-pass filter is performed before a subsequent article G enters the weighing conveyor 7 and a large transient response vibration signal appears immediately after the preceding article G leaves the weighing conveyor 7. A value obtained by averaging the load signal including the vibration noise signal subjected to the filter processing is used as a zero point correction value, and zero adjustment is performed using a value obtained by averaging N times of the zero point correction value as a final zero point correction value.

Japanese Examined Patent Publication 4-51770

  However, according to Patent Document 1, even if the output signal of the low-pass filter during the period in which the transient response vibration signal appears is averaged, it is inevitable that the zero correction value varies if the transient response vibration signal has a large oscillation amplitude.

  In addition, in the subsequent conveyance line of the production apparatus with high production capacity, the articles are continuously conveyed at short conveyance intervals and fed to the measuring conveyor. For this reason, before the preceding articles whose weights are measured by the weighing conveyor are carried out to the weighing conveyor before the articles are carried out from the weighing conveyor, the articles are continuously sent to the weighing conveyor without interruption. As it is carried in, there is almost no period of no load where no articles are present on the weighing conveyor.

  Therefore, when applying Patent Document 1 to a conveyance line downstream of a production apparatus with high production capacity, there is rarely an unloaded state in which no articles are present on the weighing conveyor, so the zero point weight value is measured only rarely. Can not be performed, and the time interval for measuring the zero weight value becomes long, and during that time the zero fluctuates, and the old zero weight measurement value in the past and the current latest zero weight measurement value include multiple times (N There is a problem that even if the average value is determined using the zero point weight measurement value in (c), the determined average value does not represent the current zero point weight value, and the zero point adjustment may not be accurately performed.

  If the operator removes a plurality of articles on the transport line upstream of the weighing conveyor at a short time interval for zero adjustment to force a no load condition, accurate zero adjustment is possible. The removal operation of a plurality of articles needs to be performed in a short time interval, and the removed articles also need to be re-weighed, and it is difficult to spend the operation time for zero adjustment.

  The present invention has been made in view of the above-described points, and there is no need to measure the zero weight value over a plurality of times, and it is measured corresponding to the zero fluctuation of the weighing conveyor at the measurement time. To make it possible to perform appropriate zero adjustment according to the zero weight value.

  In order to achieve the above object, the present invention is configured as follows.

(1) The transport and weighing device according to the present invention includes a weighing conveyor provided on a transport line for transporting an article and transporting the article, and the transport and weighing device for weighing the article while transporting the article by the weighing conveyor. There,
No-load state detection means for detecting a no-load state in which no item is present on the weighing conveyor;
Zero point weight value acquiring means for acquiring a zero point weight value which is a weight value of the weighing conveyor in the unloading time in which the weighing conveyor is in the unloaded state;
Wherein a zero weight value obtained by the zero-point weight value obtaining means, and correct without the use of other zero weight values obtained in another unloading time is the no-load time of the zero-point weight value is obtained Zero adjustment amount calculating means for calculating the zero adjustment amount;
And a zero point adjusting unit configured to adjust the zero point of the measuring conveyor by the zero point adjusting amount calculated by the zero point adjusting amount calculating unit.

According to the present invention, to get the zero weight value is the weight value in the unloaded state of the weighing conveyor, the obtained zero weight values, obtained in another unloading time and unloading time the zero weight value that is obtained Since the zero adjustment of the weighing conveyor is performed when the zero weight value is obtained by using the other zero weight adjustment amount, the zero adjustment amount is calculated using the obtained zero adjustment value. According to the reliability, the zero point adjustment amount can be calculated by correcting the zero point so as not to be excessively adjusted, and the zero point adjustment can be performed by the calculated zero point adjustment amount, each time the zero point weight value is acquired It is possible to perform zero adjustment in accordance with the present zero fluctuation amount of the weighing conveyor and in accordance with the reliability thereof.

  As a result, when applied to a transport line where the unloaded condition of the weighing conveyor rarely occurs, the time interval at which the unloaded condition where the zero point weight value can be acquired increases, and the zero point fluctuates during that time Therefore, it is impossible to perform accurate zero point adjustment as in the conventional example in which the zero value adjustment is performed by obtaining an average value with a plurality of zero point weight values including the old zero point weight value acquired in the past and the latest zero point weight value. I have not. In addition, the correction does not excessively adjust the zero point.

  (2) In a preferred embodiment of the present invention, the weighing conveyor includes a no-load time measuring means for measuring no-load time in the no-load state, and the zero point weight value acquiring means corresponds to the no-load time. The zero point weight value is acquired at a point of time, and the zero point adjustment amount calculating means calculates the zero point adjustment amount by correcting the zero point weight value according to the no-load time.

  "Point corresponding to no-load time" means a point corresponding to the length of no-load time, and if no-load time is short, the elapsed time from the start of no-load time is a short time, no-load time If it is long, the elapsed time from the start of the no-load time will be a long time point. Preferably, this time is before the end of the no-load time and is close to the end time.

  Depending on the length of no-load time of the weighing conveyor, the amount of attenuation of the transient response vibration signal caused by the detachment of the articles from the weighing conveyor will be different, the variation of the zero weight value obtained and hence the reliability of the zero weight value will be different. However, according to this embodiment, the zero weight value acquired is corrected according to the no-load time of the measuring conveyor, that is, according to the reliability thereof to calculate the zero adjustment amount, and the calculated zero adjustment amount Since the zero adjustment is performed, the zero adjustment can be performed according to the reliability of the acquired zero weight value.

  (3) In a preferred embodiment of the present invention, the zero adjustment amount calculating means corrects the zero adjustment amount on the basis of a conversion coefficient for converting the zero weight value into the zero adjustment amount. The coefficient is determined so as to convert the zero weight value into a zero adjustment amount having a smaller absolute value than the zero weight value as the unloading time is shorter.

  As the no-load time of the weighing conveyor is shorter, the amount of attenuation of the transient response vibration signal generated by the detachment of the article from the weighing conveyor is smaller and the amplitude of the transient response vibration signal is larger, so the variation of the obtained zero point weight value is larger It will be unreliable. According to this embodiment, as the no load time is shorter, the acquired zero weight value is converted into a zero adjustment amount having a smaller absolute value than the zero weight value. Adjustment can be avoided.

  (4) In another embodiment of the present invention, the zero adjustment amount calculation means calculates the zero weight value based on a saturation zero adjustment amount which regulates the absolute value of the zero adjustment amount according to the no-load time. The zero adjustment amount is corrected to calculate the saturation adjustment amount, and the saturation zero adjustment amount is set so as to restrict the absolute value smaller than the zero weight value as the no-load time is shorter.

  As the no-load time of the weighing conveyor is shorter, the amount of attenuation of the transient response vibration signal generated by the detachment of the article from the weighing conveyor is smaller and the amplitude of the transient response vibration signal is larger, so the variation of the obtained zero point weight value is larger It will be unreliable. According to this embodiment, the absolute value of the zero adjustment amount calculated by correcting the acquired zero weight value is restricted to be smaller than the zero weight value as the no load time is shorter, so the zero weight value with large variation is used. It is possible to avoid that a large misadjustment of the zero point is performed.

  (5) In still another embodiment of the present invention, a setting unit operated to set the conversion coefficient or the saturation zero adjustment amount is provided.

  According to this embodiment, it is possible to set the conversion coefficient and the saturation zero adjustment amount which define the degree of correction for correcting the acquired zero weight value and calculating the zero adjustment amount by the operation of the setting means.

According to the present invention, the zero point weight value to calculate the zero point adjustment amount to correct without the use of other zero weight values obtained in another unloading time and unloading time of the zero-point weight value is obtained Since the zero adjustment of the measuring conveyor is performed by the calculated zero adjustment amount, it becomes possible to adjust the zero weight value by the zero adjustment amount corrected according to the reliability thereof, and the zero weight value can be adjusted as in the conventional example. There is no need to acquire multiple times and calculate the average of multiple zero weight values, and each time a zero weight value is acquired, it responds to the zero fluctuation of the current weighing conveyor and its reliability The zero point adjustment can be performed using the zero point adjustment amount according to

  As a result, when applied to a transport line where the unloaded condition of the weighing conveyor rarely occurs, the time interval at which the unloaded condition where the zero point weight value can be acquired increases, and the zero point fluctuates during that time Therefore, as in the conventional example in which the average value is determined by using a plurality of zero point weight values including the old zero point weight value acquired in the past and the latest zero point weight value, as in the conventional example in which the zero point adjustment is performed The zero point weight value is not shown, and accurate zero point adjustment can not be performed.

FIG. 1 is a schematic configuration view of an article conveying system provided with a conveyance measuring device according to an embodiment of the present invention. FIG. 2 is a block diagram of the main part of the control device of FIG. It is a figure which shows the conveyance space | interval of a prior | preceding article and a subsequent article. FIG. 4 is a view showing a configuration example of the filter processing means. FIG. 5 is a diagram for explaining the response time of the filter processing means of FIG. FIG. 6 is a diagram showing the relationship between the no-load time of the weighing conveyor and the conversion factor for correcting the zero weight value. FIG. 7 is a flowchart showing an acquisition process of data for calculating the zero weight value. FIG. 8 is a flowchart showing the zero point adjustment process. FIG. 9 is a diagram showing the relationship between the no-load time of the weighing conveyor and the saturation zero adjustment amount for correcting the zero weight value. FIG. 10 is a view showing a configuration example of another filter processing means. FIG. 11 is a schematic view in the vicinity of the weighing conveyor of the weight sorting machine.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration view of an article transfer system including a weight sorting machine as a transfer and weighing device according to an embodiment of the present invention.

  The goods conveyance system of this embodiment is equipped with the goods production device 3 which has the filling apparatus 1 and volume packaging apparatus 2 of volume capacity type. The weight of each of the articles G measured by the weight sorting machine 4 installed on the downstream side of the transport direction (right direction in the drawing) of the transport line is measured. The products are sorted into non-defective products and defective products by the non-sorting device. In the product production device 3, the container supplied with a predetermined volume of raw material is filled by the filling device 1 with respect to a container supplied from a container supply device (not shown), and the container filled with the raw material It is packaged in a form and sequentially taken out as an article G. The transported articles G are sequentially transported by the transport conveyor 5 at intervals. The commodity production device 3 may be a combination balance or the like for combining and weighing articles in a predetermined weight range and discharging instead of the filling device 1.

  The weight sorting machine 4 feeds the articles G from the transport conveyor 5 constituting the transport line of the articles G to the weighing conveyor 7 and the weighing conveyor 7 supported by the load sensor 10 comprising load cells and the like. A delivery conveyor 8 for delivering the articles G from the weighing conveyor 7 to a distribution apparatus (not shown), an article sensor 12 for detecting articles carried in the weighing conveyor 7, a load signal from the load sensor 10 and an article sensor A controller 11 is provided to measure the weight value and the zero point weight value of the article G as described later based on the detection output from the control unit 12 and to control each part.

  The article sensor 12 is, for example, a photo sensor, and is disposed between the infeed conveyor 6 and the weighing conveyor 7 to detect the article G immediately before being carried into the weighing conveyor 7.

  The control device 11 measures the weight of the articles G conveyed by the weighing conveyor 7 and controls the distribution device to thereby select an appropriate product having a weight within a predetermined range, a lightweight product having a weight less than the predetermined range, and a predetermined range. Sort and sort into oversized items.

  FIG. 2 is a block diagram of the main part of the control device 11 of FIG. 1, and the parts corresponding to FIG.

  The controller 11 includes an amplifier 15 for amplifying an analog load signal from the load sensor 10, an A / D converter 16 for converting an analog load signal from the amplifier 15 into a digital load signal, and an A / D converter 16 Filter processing to attenuate vibration noise and the like included in the digital load signal to calculate the weight value and zero point weight value of the article, etc., and the entire weight sorting machine 4 including the conveyors 6 to 8 and the distribution device It comprises an arithmetic control unit 17 to control, an input unit 18 as setting means having operation keys operated for various settings and the like, and a display unit 19 to display measurement results and the like. The input unit 18 and the display unit 19 may be configured by a touch panel in which they are integrated.

  The arithmetic control unit 17 includes a CPU, a memory in which data such as control programs and weight values are stored, etc., and constitutes filtering processing means described later, and is a zero point which is a weight value of the weighing conveyor 7 in an unloaded state. Zero point weight value acquiring means for acquiring weight value, zero point adjustment amount calculating means for calculating the zero point adjustment amount as described later based on the acquired zero point weight value, and zero point adjustment of the measuring conveyor 7 by the calculated zero point adjustment amount Function as zero adjustment means for The arithmetic control unit 17 receives the detection output of the article sensor 12 and measures the time interval between the preceding article and the subsequent article based on the detection output of the article sensor 12. The arithmetic control unit 17 measures, together with the article sensor 12, no-load state detection means for detecting a no-load state in which no article is present on the measuring conveyor 7 and measures no-load time as no-load time. The load time measuring means is configured.

  In the weight sorter 4, in order to measure the weight of the article with high accuracy, the zero point fluctuation due to the change of the ambient temperature and humidity, or the application of an excessive load to the measuring conveyor 7, the deposit, etc. It is necessary to make corrections by performing zero adjustment. In order to perform the zero point adjustment, it is necessary to measure a zero point weight value which is a no-load state weight value in which no article G is present on the measuring conveyor 7.

  For example, since the articles are continuously transported at short transport intervals and fed to the weighing conveyor 7 in the subsequent transfer line of a production apparatus with high production capacity, there is rarely an opportunity for the weighing conveyor 7 to be unloaded. . For this reason, in the above-mentioned patent document 1 which performs the zero point adjustment by calculating the average value of a plurality of zero point weight measurement values, the time interval at which the no-load state occurs becomes long, and the zero point fluctuates during that time. There is a problem that zero adjustment may not be possible.

  In this embodiment, in the case of the conveyance line after the production apparatus with high production capacity, when the conveyance interval of the articles is rarely extended and the no-load state of the weighing conveyor 7 occurs, the opportunity is caught and it is even little by little It ensures that the zero adjustment can be performed, and performs zero adjustment every time an unloaded condition occurs, regardless of the unloaded condition that has occurred before that.

  The conveyance interval of the article fluctuates due to various factors such as sliding of the article or long and short control of the raw material filling time of the commodity production apparatus 3 in order to follow the density change of the raw material. There is also a change in no-load time where no

  The convergence degree of the amplitude of the transient response vibration signal of the weighing conveyor 7 generated when the preceding article leaves the weighing conveyor 7 increases as time passes, and the amplitude of the transient response vibration signal decreases as time passes. Become.

  Therefore, the transient response vibration signal converges and its amplitude becomes smaller, and the amplitude of the transient response vibration signal becomes smaller as the no-load time starting from the time when the preceding article leaves the weighing conveyor 7 and becomes unloaded is longer. The period becomes stable and the waveform becomes regular.

  In this embodiment, the zero weight is measured at a time corresponding to the no load time, that is, at a time according to the length of the no load time, specifically, at the end of the no load time. By measuring the zero point weight by waiting until the last timing of the no-load time in this way, the influence of the transient response vibration signal is avoided, and the zero point weight is measured as accurately as possible.

  As the no-load time of the weighing conveyor 7 is shorter, the zero amplitude value of the large variation is measured under the influence of the large amplitude of the transient response vibration signal due to the detachment of the preceding article from the weighing conveyor 7, and the no-loading time is measured. The longer the signal, the smaller the amplitude of the transient response vibration signal and the less the influence thereof, and the stable and accurate zero weight value with less variation is measured.

  That is, the shorter the no-load time of the measuring conveyor 7, the lower the reliability of the measured zero weight value, and the longer the no-load time, the higher the reliability of the measured zero weight value.

  In this embodiment, the zero weight value itself is measured in order to ensure that the zero adjustment can be performed according to the latest zero fluctuation of the weighing conveyor 7 even if it catches the rare occasion of no-load occurrence and gradually. Instead of performing zero adjustment of the weighing conveyor 7, the zero weight value is corrected and converted into a zero adjustment amount according to the reliability of the measured zero weight value, and the zero adjustment of the weighing conveyor 7 is performed using this zero adjustment amount. To do.

  As described above, the reliability of the measured zero weight value becomes lower as the unloading time of the measuring conveyor 7 becomes shorter, and becomes higher as the unloading time becomes longer. Therefore, in this embodiment, a zero adjustment amount for correcting the measured zero weight value according to the length of no-load time of the weighing conveyor 7, and actually adjusting the corrected zero weight value to the zero of the weighing conveyor 7. And

  Specifically, the measured zero weight value is reduced according to the unloading time of the measuring conveyor 7, that is, the absolute value of the measured zero weight value is reduced.

  The degree to which the absolute value of the measured zero weight value is reduced (hereinafter also referred to as “reduction degree”) corresponds to the length of no-load time of the measuring conveyor 7. If the no-load time is short, the reduction degree is greatly increased. If the no load time is long, reduce the degree of contraction. As described later, when the no-load time is short to the extent that effective zero adjustment can not be performed, the zero adjustment is not performed, and the no-load time is long enough to measure the sufficiently stable zero weight value. Does not reduce the measured zero weight value at all.

  As the no load time is short, the reduction degree is increased, and when the no load time is long, the reduction degree is decreased. Therefore, the shorter the no load time of the measuring conveyor 7, that is, the larger the zero point weight value of the variation measured The degree of reduction of the absolute value of the zero point weight value is increased, and the zero point adjustment amount of a smaller absolute value is converted to zero point adjustment. Therefore, it is possible to avoid a large misadjustment of the zero point due to a large variation in the inaccurate zero point weight value.

  Also, as the no-load time of the measuring conveyor 7 is longer, that is, as the precise zero point weight value with smaller variation, the degree of reduction of the absolute value of the measured zero point weight value decreases, and the zero point closer to the measured zero point weight value It is converted to an adjustment amount and zeroed. Therefore, as the accurate zero weight value with less variation is converted into a zero adjustment amount close to the zero weight value, the zero adjustment is performed.

  Next, based on FIG. 3, the no-load time of the weighing conveyor 7 will be described.

  In this embodiment, the time between the detection of the preceding article G0 by the article sensor 12 installed between the measuring conveyor 7 and the in-feed conveyor 6 and the detection of the subsequent article G1 by the article sensor 12 The no-load time which is the time of no-load state in which the article G is not present on the measuring conveyor 7 is calculated as described later. The measured zero point weight value is corrected according to the calculated length of no-load time of the measuring conveyor 7 and converted into a zero point adjustment amount.

  In FIG. 3, when the trailing end of the preceding article G0 just leaves the measuring conveyor 7 without the subsequent article G1 being detected by the article sensor 12, the measuring conveyor reaches the position p. When No. 7 is unloaded, the no-load time is started, and the leading end of the preceding article G0 reaches the position a, the no-load time when no articles are present on the measuring conveyor 7 becomes Ta, and the preceding article G0 When the front end of H reaches position b, the unloading time of the measuring conveyor 7 becomes Tb.

  The time taken for the rear end of the article G0 to be released from the measuring conveyor 7 and the start of the no-load time after the leading end of the preceding article G0 is detected by the article sensor 12 Then, when the time interval between the measured articles is Tx, the no-load time Ta of the weighing conveyor 7 when the leading end of the preceding article G0 reaches the position a (when Tx = ta) is Ta = Tx-tp = ta-tp, and the no-load time Tb of the weighing conveyor 7 when the leading end of the preceding article G0 reaches the position b (when Tx = tb) is Tb = tb-tp It becomes.

  The no-load start time tp at which the no-load time of the weighing conveyor 7 starts is a fixed value when the type of article (the length of the article), the length of the weighing conveyor 7, and the transport speed of the weighing conveyor 7 are defined. Since these values are set and input from the input unit 18, the no-load start time tp is calculated based on these values. That is, the no-load start time tp is constant according to the setting when the type of the article to be weighed (the length of the article), the length of the measuring conveyor 7, and the transport speed of the measuring conveyor 7 are set. The value is calculated.

Assuming that the measurement value of the time interval between the articles is Tx, the no-load time Tx ′ of the weighing conveyor 7 is Tx ′ = Tx−tp as described above.
It is calculated as

  In this embodiment, the absolute value of the zero weight value measured as described above is reduced according to the length of the no-load time Tx ′ of the measuring conveyor 7 to calculate the zero adjustment amount. Determines the conversion coefficient ka for converting the zero weight value into the zero adjustment amount according to the length of the no-load time Tx 'of the weighing conveyor 7, and performs zero adjustment by multiplying the measured zero weight value by the conversion coefficient ka I try to make it a quantity.

  The conversion coefficient ka (= 0 to 1) is made to gradually increase from the minimum value ka = 0 to the maximum value ka = 1 as the no-load time Tx ′ of the measuring conveyor 7 becomes longer.

  Therefore, as the no-load time Tx 'is shorter, the conversion coefficient ka is set to “0” or a value close thereto, and the measured zero weight value is multiplied by the conversion coefficient ka having a value close to or “0”. The degree of reduction is increased, converted to a smaller zero adjustment amount, and zero adjustment is performed. When the conversion coefficient ka is "0" and therefore the zero adjustment amount is "0", zero adjustment is not performed.

  Further, as the load time Tx 'is longer, the conversion coefficient ka is set to “1” or a value close thereto, and the measured zero weight value is multiplied by the conversion coefficient ka “1” or a value close thereto ”. Becomes smaller and is converted to the zero adjustment value of the measured zero weight value or a value close to it, and the zero adjustment is performed.

  If the no load time Tx 'of the weighing conveyor 7 is short, the influence of the transient response vibration signal due to the detachment of the preceding article from the weighing conveyor 7 is large, and the variation of the measured zero weight value becomes large. As the '' is shorter, the measured zero weight value is multiplied by a conversion coefficient ka of "0" or similar to convert it into a smaller zero adjustment amount, whereby the zero weight value of the large variation is obtained. It tries to avoid that a big misadjustment is performed.

  In addition, when the no-load time Tx 'of the measuring conveyor 7 is long, the transient response vibration signal converges and the variation of the measured zero weight value becomes small. Therefore, the longer the no-load time Tx', the measured zero weight value Is multiplied by a conversion coefficient ka close to "1" to convert it into a measured zero weight value or a zero adjustment amount closer to it and perform zero adjustment.

  As described above, the conversion coefficient ka is determined according to the no-load time Tx 'of the weighing conveyor 7, and the measured zero weight value is multiplied by the conversion coefficient ka to calculate the zero adjustment amount. Although the zero adjustment is performed, in this embodiment, in order to measure the zero weight value, the load signal measuring the zero weight is filtered by the filtering means having a plurality of filters having various response characteristics. I am trying to do it.

  In the above-mentioned patent document 1, in order to filter the load signal in a short unloading time until the preceding article is separated from the measuring conveyor and the subsequent article is loaded, the measurement of the zero weight has a fast response characteristic. Only a low pass filter for high frequency component removal is used.

  For this reason, in patent document 1, the filter process of the optimal characteristic according to the no-load time of a fluctuation | variation weighing conveyor may not be performed, for example, the response characteristic of a filter is late compared with the no-load time of the measurement conveyor 7. If it is too much, the load signal component measured when the articles are still present on the weighing conveyor is included in the filter operation, and there is a problem that the filter output does not accurately represent the zero weight value.

  On the other hand, if the response characteristic of the filter is too fast compared to the no-load time of the weighing conveyor 7, even when the no-loading time of the weighing conveyor 7 is long, the variation in which the amplitude of the transient response vibration signal is sufficiently attenuated There is a problem that it is not possible to obtain a small zero weight value of.

  In this embodiment, it is configured as follows so that filtering processing can be performed according to the no-load time in which the weighing conveyor 7 is in the no-load state, and stable and accurate zero point weight values can be obtained.

  That is, in this embodiment, the filter processing means having a plurality of filters having various response characteristics is provided, the no-load time of the measuring conveyor 7 is measured, and the filter having the response characteristics corresponding to the measured no-load time. The output is selected to obtain the zero weight value.

  A plurality of filters having different response characteristics of the filter processing means are configured by connecting a plurality of filter elements in a cascade, and a load signal for measuring a zero weight value is passed through the plurality of filters of the filtering means.

  The weight value of the article is measured from the filtered load signal as in the conventional case as in the prior art.

  When multiple filters are cascade-connected, the load signal output from each filter has different response characteristics and smoothing characteristics, and the response characteristics are slower as the output from the filter connected in the latter stage, that is, the output response time Becomes longer, the smoothing characteristic becomes larger, and the amount of attenuation of the vibration component becomes larger.

  On the contrary, as the output from the filter connected in the previous stage, the response characteristic becomes faster, that is, the output response time becomes shorter, the smoothing characteristic becomes smaller, and the attenuation amount of the vibration component becomes smaller.

  In this embodiment, the no-load time of the weighing conveyor 7 is measured, and each output point of the plurality of filters is selected according to the no-loading time of the weighing conveyor 7. The load signal filtered by the response characteristic filter is read to obtain a zero weight value.

  Specifically, the shorter the no-load time of the weighing conveyor 7, the faster the response characteristic, ie, the shorter the response time of the filter output is selected, the longer the no-loading time of the weighing conveyor 7, the slower response characteristic. That is, the output of the filter having a long response time is selected.

  Thus, the output of the filter of the response characteristic according to the no-load time of the weighing conveyor 7 is read to obtain the zero weight value, so the response time of the filter is too long compared to the no-loading time. The load signal component sampled when the article is still present is not included in the filter operation, so that it is possible to obtain an accurate zero point weight value with no error on the level of the load signal.

  Also, as the no-load time of the weighing conveyor 7 is longer, the output of the filter having a slow response characteristic and a large smoothing characteristic is read to obtain a zero weight value, so that the articles included in the load signal are detached from the weighing conveyor 7 In this case, the degree of smoothness of the transient response signal is increased, that is, the degree of attenuation of the transient response vibration signal is increased, so that a stable and accurate zero weight value with less variation can be obtained.

  The analog load signal output from the load sensor 10 of the weighing conveyor 7 is amplified by the amplifier 15 shown in FIG. 2 and the A / D converter 16 performs A sampling at short sampling intervals Δt, for example, every 1 msec (Δt = 1 msec). The digital load signal which is / D converted and read as a digital load signal to the operation control unit 17 and which measures the zero weight value is filtered by the filter processing means described later. Also, the weight value of the article is calculated by means of a digital load signal filtered by a conventional filter.

The filter output value of the digital load signal is Wa, the filter output value (initial load) of the digital load signal at no load of the weighing conveyor 7 stored in advance in the adjustment stage is Wi, and a load such as a known weight is weighed on the weighing conveyor 7 Assuming that K is a span coefficient determined by placing on W, and Wz is an integrated value of the zero point fluctuation amount generated during operation operation, the weight measurement value Wn of the article when the article is present on the weighing conveyor 7 is
Wn = K (Wa-Wi)-Wz (1)
It is calculated as

  The load signal for obtaining the span coefficient K and the initial load Wi in the equation (1) is, for example, the output of the filter with the slowest response characteristic of the filter processing means described later.

  The weight measurement value Wn based on the output value Wa obtained by the filter having a response characteristic according to the no-load time obtained by the filter processing means described later obtained when the article is not present on the weighing conveyor 7 is unloaded by the weighing conveyor 7. If Wn ≠ 0, the value of Wn means a zero point fluctuation amount, and is a value to be zero-adjusted.

  The weight measurement value Wn of the article when the article is present on the weighing conveyor 7 is the same as the conventional filtering as described above, that is, the article G is separated from the infeed conveyor 6 and placed on the weighing conveyor 7 Based on the filter output Wa by the filter having the response characteristic, the time taken for the article G to reach the position d just before contacting the delivery conveyor 8 from the position of FIG. It is calculated from the equation.

  FIG. 4 is a diagram showing filter processing means configured in the arithmetic control unit 17. As shown in FIG.

  A digital load signal Wa 'from the A / D converter 16 for converting an analog load signal into a digital load signal at a sampling interval (Δt = 1 msec) of 1 msec is read into the filter processing means 20 of this embodiment.

  The filter processing unit 20 serially connects N1 cell memories S1 (0) to S1 (N1-1) capable of storing one A / D sampled data A / D converted by the A / D converter 16. Storing the shift register SR1, the average value calculation element 1 / N1 for calculating the average value of the outputs of the cell memories S1 (0) to S1 (N1-1), and the output A1 of the average value calculation element 1 / N1 A shift register SR2 in which N2 cell memories S2 (0) to S2 (N2-1) are connected in series, and an average value for calculating the average value of the outputs of the cell memories S2 (0) to S2 (N2-1) A shift register SR3 in which N3 = q + r pieces of cell memories S3 (0) to S3 (q + r-1) storing the arithmetic element 1 / N2 and the output A2 of the average value arithmetic element 1 / N2 are serially connected, and each cell Memory output average A plurality of average value computing device 1 / q, 1 / for calculating each (q + 1), ···, 1 / (q + r'), ···, and a 1 / (q + r).

  In the filter processing means 20, the cell memory S1 (0) to S1 (N1-1) of the shift register SR1 is loaded each time the digital load signal Wa 'from the A / D converter 16 is newly read every .DELTA.t = 1 msec. 4 are sequentially shifted to the right in FIG. 4 to store the digital load signal newly read into the leftmost cell memory S1 (0).

  The average value calculation element 1 / N1 calculates the average value of the outputs of the cell memories S1 (0) to S1 (N1-1) every Δt, and outputs the average value to the shift register SR2.

  The shift register SR2 sequentially shifts the data stored in the cell memories S2 (0) to S2 (N2-1) to the right in FIG. 4 each time the output A1 from the average value operation element 1 / N1 is input every .DELTA.t. Shift and store the new input in the leftmost cell memory S2 (0).

  The average value calculation element 1 / N2 calculates the average value of the outputs of the cell memories S2 (0) to S2 (N2-1) every Δt, and outputs the average value to the shift register SR3.

  The shift register SR3 sequentially stores data stored in the cell memories S3 (0) to S3 (q + r-1) to the right in FIG. 4 every time the output A2 from the average value operation element 1 / N2 is input every .DELTA.t. Shift and store a new input in the leftmost cell memory S3 (0).

  A plurality of average value operation elements 1 / q, 1 / (q + 1),..., 1 / (q + r '),..., 1 / (q + r) correspond to corresponding cell memories S3 (0) to S3 ( q-1), S3 (0) to S3 (q), ..., S3 (0) to S3 (q + r'-1), ..., S3 (0) to S3 (q + r-1) Calculates and outputs the average value.

  Here, the average value calculation element 1 / (q + r ′) is representative of average value calculation elements from the average value calculation element 1 / q at the left end to the average value calculation element 1 / (q + r) at the right end in FIG. In other words, when r ′ = 0 to r and r ′ = 0, this corresponds to the average value operation element 1 / q at the left end, and when r ′ = r, the average value operation element at the right end It corresponds to 1 / (q + r).

  For example, the average value calculation element 1 / q of the plurality of average value calculation elements 1 / q, 1 / (q + 1),..., 1 / (q + r ′),. The addition value I (0) of the q outputs of the cell memories S3 (0) to S3 (q-1) is divided by q to calculate an average value I (0) / q, and the average value calculation element 1 / (1 q + 1) calculates the average value I (1) / (q + 1) by dividing the sum I (1) of the q + 1 outputs of the cell memories S3 (0) to S3 (q) by q + 1 and calculating the average value The element 1 / (q + r ') divides the sum I (r') of q + r 'outputs of the cell memories S3 (0) to S3 (q + r'-1) by q + r' to obtain an average value I (r '). ) / (Q + r ') is calculated, and the average value calculation element 1 / (q + 1) calculates the sum I (r) of q + r outputs of the cell memories S3 (0) to S3 (q + r-1) by q + r. Calculated to calculate an average value I (r) / (q + r).

  As described above, the shift register SR3 outputs a plurality of average values of the outputs of the corresponding cell memories in the direction in which the response time increases sequentially for each cell memory connected to the cell memory S3 (q-1) and thereafter. Average value calculation elements 1 / q, 1 / (q + 1), ... 1 / (q + r '), 1 / (q + r) are provided, and dependent on the length of no-load time Tx' of the measuring conveyor 7. The response time of the output of the connected filter can be coped with by Δt.

  In this embodiment, one of the plurality of average value operation elements 1 / q, 1 / (q + 1), ..., 1 / (q + r '), ..., 1 / (q + r) is weighed. It selects according to no-load time Tx 'of the conveyor 7, makes it a filter output by the filter processing means 20, and acquires a zero weight value from the filter output.

  Between the adjacent average value operation elements 1 / q, 1 / (q + 1),..., 1 / (q + r ′),. It can be considered that each cell memory S3 (q) to S3 (q + r-1) and each addition element are sequentially connected, and each filter is sub-connected.

  The time required to sample data to be stored in N1 cell memories S1 (0) to S1 (N1-1) of shift register SR1 is set to correspond to one cycle of the characteristic vibration signal of weighing conveyor 7. The shift register SR1 and the average value calculation element 1 / N1 remove the natural vibration noise signal generated when the article leaves the weighing conveyor 7 at a large attenuation rate.

  Also, the time required to sample data to be stored in the N2 cell memories S2 (0) to S2 (N2-1) of the shift register SR2 corresponds to one cycle of AC signal noise (line noise). The shift register SR2 and the average value calculation element 1 / N2 are set to remove AC signal noise at a large attenuation rate.

  In any case, in measuring the zero weight value, a filter suitable for removing the noise signal to be removed with a large attenuation factor is constructed.

  5 shows the outputs A1 and A2 of the average value calculation elements 1 / N1 and 1 / N2 and the average value calculation elements 1 / q and 1 / (q + 1) with respect to the digital weight signal Wa 'input to the filter processing means 20 of FIG. ),..., 1 / (q + r ′),..., 1 / (q + r). In FIG. 5, ○ indicates the digital load signal Wa ′ input from the A / D converter 16 every Δt, and this digital load signal Wa ′ is the N1 cell memory S1 (0) of the shift register SR1. .About.S1 (N1-1) are sequentially input, and hence the outputs of the respective cell memories S1 (0) to S1 (N1-1).

  The crosses indicate the calculation results of the average value calculation element 1 / N1 obtained by dividing the addition value of the outputs of the cell memories S1 (0) to S1 (N1-1) by N1 at every Δt, ie, the average value calculation element 1 / N1. Output data string A1. The digital load signal Wa 'is read into the cell memory S1 (0) of the shift register SR1 until time T = 0 from (N1-1) .DELTA.t until the calculation result of the average value calculation element 1 / N1 is obtained. The time has elapsed, and this time (N1-1) Δt corresponds to one cycle of the natural vibration signal of the weighing conveyor 7 described above. The calculation results of the average value calculation element 1 / N1 are sequentially stored in the cell memories S2 (0) to S2 (N2-1) of the shift register SR2.

  The Δ marks are average value operation elements obtained by dividing the addition value of the outputs of the cell memories S2 (0) to S2 (N2-1) storing the data A1 of the operation results of the average value operation element 1 / N1 by N2 for every Δt. It is the data string A2 of the output of the average value calculation element 1 / N2, that is, the calculation result of 1 / N2. Until the calculation result of the average value calculation element 1 / N2 is obtained, the time of (N2-1) Δt has elapsed from the time when the calculation result of the average value calculation element 1 / N1 is obtained. N2-1) Δt corresponds to one cycle of the AC noise signal (line noise) described above. The calculation results of the average value calculation element 1 / N2 are sequentially stored in the cell memories S3 (0) to S3 (q + r-1) of the shift register SR3.

The calculation result of the average value calculation element 1 / N2 is a multiple moving average data including two average value calculation processes.
The output I (0) / q of the average value operation element 1 / q obtained by dividing the sum I (0) of the q outputs of the cell memories S3 (0) to S3 (q-1) of the shift register SR3 by q Is the output of the filter with the shortest response time obtained from the filtering means 20, and the zero weight value is calculated from the output of this filter. When the output of the average value calculation element 1 / q is obtained, the average value of the cell memories S2 (0) to S2 (N2-1) of the shift register SR2, ie, the output A2 of the average value calculation element 1 / N2 It is a time point at which the time of (q-1) · Δt has elapsed from the obtained time point.

  Also, from this time point T = 0 when the digital load signal Wa 'is read into the cell memory S1 (0) of the shift register SR1, {(N1-1) + (N2-1) + (q-) 1) The time when the time of .DELTA.t has elapsed, and this time is the average of the output point of the filter corresponding to the added value I (0) of the outputs of the cell memories S3 (0) to S3 (q-1) It is a response time to the value calculation element 1 / q.

  Let this time {(N1-1) + (N2-1) + (q-1)}. DELTA.t be the shortest time at which the zero point weight value can be measured when the measuring conveyor 7 is not loaded. The shortest no-load time (hereinafter also referred to as "first no-load time") at which the zero weight value can be measured can be shown as Ta in FIG. Further, at time T = 0 when the digital load signal Wa 'is read into the cell memory S1 (0) of the shift register SR1, the rear end portion of the preceding article G0 just leaves the weighing conveyor 7 in FIG. The tip corresponds to the no-load start time tp, which is the time to reach the position p.

Assuming that the first no-load time Ta is, for example, 100 msec elapsed from the no-load start time Tx = tp of the measuring conveyor 7 determined by the length of the measuring conveyor 7, the article length, and the transfer speed of the measuring conveyor 7. ,
Ta = {(N1-1) + (N2-1) + (q-1)} · Δt
= 100 (msec)
It is.

  In this example, since [Delta] t = 1 msec as described above, [(N1-1) + (N2-1) + (q-1)] = 100 cell memories are prepared.

  The cell memory S3 (0) to S3 (q + r-1) having the largest number from the average value calculation element 1 / q, which is the output point of the average value of the smallest cell memories S3 (0) to S3 (q-1) of the shift register SR3. The average value operation element 1 / (q + r ') representatively shows up to the average value operation element 1 / (q + r) which is the output point of the average value of the digital load signal Wa'. 0) is the filter output value at the time when the time of {(N1-1) + (N2-1) + (q + r'-1)}. DELTA.t has elapsed from time T = 0 read into r), r ' The value of is associated with the value of the unloading time Tx ′ of the measuring conveyor 7 to be measured as follows.

Tx ′ = {(N1-1) + (N2-1) + (q + r′-1)} · Δt
= Ta + r '· Δt
Then, the output I (r ') / (q + r') of the corresponding average value calculation element 1 / (q + r ') is selected by the measured value of the no-load time Tx' of the measuring conveyor 7.

  It converges until the amplitude of the transient response vibration signal generated when an article leaves the weighing conveyor 7 is small enough to define a sufficiently stable filter output and thus a response time Tb that can obtain an accurate zero weight value with small variation. The response time Tb is the response to the average operation element 1 / (q + r) which outputs the average value of the cell memories S3 (0) to S3 (q + r-1) when the cell memory in the shift register SR3 is the largest. Correspond to time.

  The response time Tb at which this sufficiently stable filter output can be obtained can be shown as no-load time Tb (= Tx-tp) in FIG. Here, this no-load time Tb is, for example, the same as no-load start time tp (Tb = tp), that is, the time interval Tx between articles is twice the no-load start time tp (Tx = 2 · When tp), it is assumed that a sufficiently stable filter output can be obtained.

The no-load time Tb (hereinafter also referred to as "second no-load time") at which this sufficiently stable filter output can be obtained is the sum I (r) of the outputs of the cell memories S3 (0) to S3 (q + r-1). It is the response time to the averaging operation element 1 / (q + r) which is the output point of the corresponding filter, and as shown in FIG. 5, the digital load signal Wa 'is read into the cell memory S1 (0) of the shift register SR1. It is the time when the time of {(N1-1) + (N2-1) + (q + r-1)}. DELTA.t has elapsed from the time T = 0. Therefore, assuming that the second no-load time Tb is equal to the no-load start time tp,
Tb = {(N1-1) + (N2-1) + (q + r-1)} · Δt
= Ta + r · Δt = 100 + r = tp (∵ Δt = 1 msec)
In addition to 100 of the first no-load time Ta, r more cell memories are prepared so that

  When the no-load time Tx 'of the measuring conveyor 7 is equal to or more than the second no-load time Tb, it is possible to obtain a sufficiently stable filter output, and hence an accurate zero weight value with small variation. Select the data to be output from (q + r).

  In this embodiment, when the no-load time Tx ′ of the weighing conveyor 7 is less than the first no-loading time Ta, the transient response vibration signal due to the detachment of the article from the weighing conveyor 7 is large, and effective zero adjustment is performed. If the no-load time Tx 'is greater than or equal to the first no-load time Ta and less than the second no-load time Tb, the filter output corresponding to the no-load time Tx' is selected. Zero adjustment is performed, and when the no-load time Tx 'exceeds the second no-load time Tb, a sufficiently stable filter output can be obtained, so the filter output corresponding to the second no-load time Tb is selected and the zero is adjusted. I am trying to make adjustments.

  As the unloading time Tx 'of the weighing conveyor is longer, the transient response vibration signal generated when an article is removed from the weighing conveyor 7 converges and its amplitude becomes smaller, and in addition, the unloading time Tx' of the weighing conveyor 7 Since processing can be performed with a filter having a long response time according to the length, stable and accurate zero weight values with less variation can be obtained from any point of the transient response characteristic and the attenuation characteristic of the filter.

  In this embodiment, as described above, as the no-load time Tx 'of the measuring conveyor 7 is shorter, that is, as the variation in the measured zero weight value is larger and the reliability is lower, the measured zero weight value 0, which is multiplied by a conversion coefficient ka or a value close thereto, converted to a zero adjustment amount smaller than the actually measured zero weight value, and zeroed, and the longer the no load time Tx ′ of the measuring conveyor 7, ie, The smaller the variation in the zero weight value and the higher the reliability, the measured zero weight value is multiplied by a conversion coefficient ka of “1” or similar to convert it into a zero adjustment amount close to the actually measured zero weight value. Adjust the zero point.

  Here, with regard to the effect of converting the measured zero weight value into the zero adjustment amount, (a) when the measured zero weight value includes a large variation component because the no-load time of the measuring conveyor 7 is short, b) Since the no-load time of the measuring conveyor 7 is long, the measured zero point weight value will be described separately in the case where only a small variation component is included.

(A) When the measured zero point weight value includes a large variation component because the no-load time of the weighing conveyor 7 is short, the shorter the no-load time of the weighing conveyor 7, the faster the response characteristics of the filter. The measured value of contains a large variation component.

  Even if the measured zero weight value includes a variation component, the larger the absolute value of the measured value of the zero weight, that is, the larger the absolute value of the measured value of the zero fluctuation, the magnitude of the actually occurring zero fluctuation, The trend in the positive or negative direction clearly appears. That is, as the actual zero point fluctuation amount is larger, the measured zero point weight value clearly shows the magnitude of the zero point fluctuation and the tendency in the plus or minus direction.

  When it is determined that the actual zero point weight variation is large and a large zero point weight value is measured, and it is determined that the variation is large depending on the no-load time Tx ′ of the measuring conveyor 7, ie, no measuring conveyor 7 When the load time Tx 'is short, the measured zero weight value is reduced by a large reduction degree by being multiplied by the conversion coefficient ka close to "0" as described above, and is converted into a small zero adjustment amount. The zero adjustment amount is obtained according to the tendency of the zero fluctuation. Therefore, for example, even in the case of a transfer line with a narrow transfer distance of articles, such as a transfer line at the latter stage of a production apparatus with high production capacity, there is little chance of no load time of the weighing conveyor 7 occurring. It is possible to perform zero adjustment in accordance with the current tendency of actual zero fluctuation by capturing few opportunities where no load time occurs.

  On the contrary, when the actual zero point weight variation is small, the actual zero point weight value is measured to a negative value as the zero point weight value because the variation is large despite, for example, a small positive value. If the no-load time Tx 'of the weighing conveyor 7 is short, the measured zero weight value is multiplied by the conversion coefficient ka close to "0" and reduced with a large reduction degree, which is extremely small. Since the zero point adjustment amount is converted, even if the zero point adjustment amount has a direction or a magnitude different from the direction of the actual zero point fluctuation, it is possible to suppress the degree of misadjustment of the zero point small.

(B) When the zero load value of the measuring conveyor 7 has a long non-load time, the measured zero point weight value includes only a small variation component. When the non-loading time of the measuring conveyor 7 is long and the variation of the load signal is small, it is stable. Since the accurate zero point weight value can be measured, the opportunity for the weighing conveyor 7 to be unloaded even if there is little opportunity for the unloading time of the weighing conveyor 7 to be a narrow transportation line. Capture the opportunity for no load, whether the zero weight value actually measured is large or small, and multiply the measured zero weight value by a conversion factor ka of "1" or similar, Calculate the zero adjustment amount of the zero weight value to be measured or a value close to it. By this, even if there is only one no-load opportunity, the zero adjustment can be accurately performed by the zero adjustment amount of the direction, the magnitude, which is close to or equal to the actual zero weight value (zero fluctuation amount) of the present measuring conveyor 7 it can.

  The conversion factor ka multiplied by the measured zero point weight value sets, for example, a function of the conversion factor according to the length of no-load time Tx 'of the measuring conveyor 7. During operation, the zero point measured when the measuring conveyor 7 is not loaded The conversion coefficient ka corresponding to the length of the no-load time Tx ′ of the weighing conveyor 7 is selected and multiplied with the weight value to calculate the zero adjustment amount with the zero weight value reduced.

FIG. 6 is a graph showing a function of the conversion factor, and the conversion factor ka of the measuring conveyor 7 is the same as that of the weighing conveyor 7 when the no load time Tx ′ is between the first no load time Ta and the second no load time Tb. It is defined as a linear function with no load time Tx 'as a parameter. In addition, you may set to a high-order function as other embodiment of this invention. In FIG. 6, a conversion coefficient ka which is a zero point adjustment amount by multiplying the zero point weight value is defined as follows according to the no-load time Tx ′.
(1) When Tx '<Ta ka = 0
When the no-load time Tx 'of the weighing conveyor 7 is less than the first no-loading time Ta, the transient response vibration signal due to the detachment of the article from the weighing conveyor 7 is large, and no effective zero adjustment can be performed. Even if the zero weight value is measured, the zero adjustment amount becomes "0". In other words, zero adjustment is not performed.
(2) When Ta ≦ Tx ′ ≦ Tb ka = {1 / (Tb−Ta)} · Tx ′ − {Ta / (Tb−Ta)}
(3) When Tx '> Tb ka = 1
When the unloading time Tx 'of the weighing conveyor 7 exceeds the second unloading time Tb, the transient response vibration signal due to the detachment of the article from the weighing conveyor 7 sufficiently converges, and a sufficiently stable accurate zero point weight value is measured If possible, the measured zero weight value itself is taken as the zero adjustment amount.

  As described above, in the first no-load time Ta to the second no-load time Tb, the conversion factor ka has a zero-point weight value and an absolute value smaller than that as the no-load time Tx 'becomes shorter. It is determined to be converted to the zero point adjustment amount.

  Next, processing up to acquisition of data for calculating the zero weight value will be described based on the flowchart of FIG.

  The processing of FIG. 7 is started at intervals of 1 msec by, for example, a clock pulse of 1 msec of a clock generation circuit built in the arithmetic control unit 17, and is processed with priority also by other processing. That is, it is executed with top priority every 1 msec.

  The arithmetic control unit 17 reads the digital load signal from the A / D converter 16 (step n1), and the filter processing means 20 shown in FIG. 4 implements the filter arithmetic processing (step n2). However, in the calculation by the average value calculation element, only multiple average calculation processing is performed by the average value calculation element 1 / N1 and the average value calculation element 1 / N2. Average value calculation elements 1 / q, 1 / (q + 1),... 1 / (q + r '),..., 1 / (q + r) are executed by another processing program.

  Next, it is judged whether or not the flag Fo is set to "1" (step n3), and when it is not set to "1", it is judged whether or not the flag Fa is set to "1". (Step n4) If not set to “1”, it is judged whether or not the article sensor 12 detects an article (Step n5), and when not detected, the process is ended. That is, in a state in which both the flag Fo and the flag Fa are "0", when the article is not detected by the article sensor 12, the time interval Tx between articles for calculating the no-load time Tx 'of the measuring conveyor 7 is counted. do not do.

  When an article is detected in step n5, the flag Fo and the flag Fa are set to "1", and the time interval Tx between articles for calculating the no-load time Tx 'of the measuring conveyor 7 is counted from the next processing cycle. It is made ready and finished (steps n6 and n7).

  In step n3, when the flag Fo is set to "1", the article is detected by the article sensor 12, and the article completely passes through the detection area, assuming that the article is passing through the detection area of the article sensor 12. The transit time measuring counter Co which measures the time until it increments is incremented (step n9), and the count value of the transit time measuring counter Co exceeds the time To when the article completely passes the detection area of the article sensor 12 It is determined whether it has become (step n10).

  When the count value of the passage time measuring counter Co is not longer than the time To for the article to completely pass through the detection area of the article sensor 12, the process proceeds to step n13, and the time for completely passing the detection area When it becomes To or more, it is assumed that the article detected by the article sensor 12 has completely passed the detection area of the article sensor 12, the flag Fo and the transit time measuring counter Co are respectively reset, and the process moves to step n13 (step n11, n12).

  At step n13, the time interval measurement counter Ca for measuring the time interval Tx between the preceding article and the subsequent article is incremented and terminated. Even when the time T0 when the article has passed through the detection area of the article sensor 12 has elapsed, the counting of the time interval measurement counter Ca is continued.

  When the flag Fo is not set to "1" in step n3 and the flag Fa is set to "1" in step n4, it is determined whether the flag Fo is set to "1". (Step n8).

  In step n8, when the flag Fo is set to "1", it is determined that the article is passing through the detection area of the article sensor 12, and the process proceeds to step n9 described above, and when not set to "1", the step Move to n14. At step n14, the time interval measurement counter Ca for measuring the time interval Tx between the articles is incremented, and the process proceeds to step n15. That is, even if the flag Fo = 0, if the flag Fa = 1, the next article has not yet reached the article sensor 12, so the time interval measurement counter Ca counts the time interval Tx between the articles. .

  In step n15, it is determined whether or not the article is detected by the article sensor 12. If the article is not detected, the non-load time Tx ′ of the measuring conveyor 7 is calculated from the count value Tx of the time interval measurement counter Ca. Tp) is calculated, and it is judged whether or not the calculated no-load time Tx 'is the second no-load time Tb or more (step n16), and when it is not the second no-load time Tb, the process is ended.

  In step n15, when an article is detected, it is assumed that the next article is detected by the article sensor 12 before the no-load time Tx 'reaches the second no-load time Tb, and the no-load time is ended. Reset to "0" (step n17), store the no-load time Tx 'at that time in the memory Mt (step n18), and set the zero adjustment start flag Fz for performing zero adjustment to "1". (Step n19), the time interval measurement counter Ca is reset (Step n20), and the cell memory S3 (0) to the zero load time Tx 'in order to obtain the zero point weight value (zero point fluctuation amount) at this time The output of S3 (q + r'-1) is stored in the memory MR and the process ends (step n21). As described later, the zero point weight value and the zero point adjustment amount are obtained by another program, and the zero point adjustment is performed. As soon as the highest priority program is executed, the program based on the zero adjustment start flag Fz = 1 is executed, so that there is no delay in the timing of the execution of the zero adjustment.

  In step n16, when the no-load time Tx 'becomes equal to or more than the second no-load interval Tb, that is, when the no-load time Tx' becomes the second load time Tb or more without arrival of the next item, The no-load time Tx 'at that time is stored in the memory Mt (step n18), the zero adjustment start flag Fz is set to "1" (step n19), and the time interval measurement counter Ca is reset (step n20).

  At this time, in order to obtain the zero point weight value (zero point fluctuation amount), the outputs of the cell memories S3 (0) to S3 (q + r-1) corresponding to the second no-load time Tb are stored in the memory MR and the process ends. (Step n21).

  In this case, that is, when the no-load time Tx 'becomes equal to or more than the second load time Tb without arrival of the next item, the flag Fa is kept at "1". If the flag Fa = 1, the process proceeds from the next processing cycle to the above steps n4, n8 and n14, and the time interval measurement counter Ca is again performed between the articles until the next article is detected by the article sensor 12 Start counting the time interval Tx.

  When the conveyor operation switch is turned on, the flag Fa is forcibly set to "1" and the process proceeds from the first processing cycle to the above steps n4, n8 and n14, and the next article is detected by the article sensor 12 Until time, the counting of the time interval Tx between the articles is started again by the time interval measuring counter Ca.

  FIG. 8 is a flowchart showing the zero point adjustment process, and FIG. 8 is a program process with lower priority than FIG. 7 in which the conversion coefficient ka and the zero point are determined by the no-load time Tx 'of the measuring conveyor 7 and the filter output data. The process which calculates weight value (zero point fluctuation amount) Wnz and zero point adjustment amount Wnza, and implements zero point adjustment is shown.

  First, it is judged whether or not the zero point adjustment start flag Fz is set to "1" (step n101), and when it is set to "1", the zero point adjustment start flag Fz is reset to "0" (step n102) The value of no-load time Tx 'of the weighing conveyor 7 stored in the memory Mt is read (step n103).

  Next, according to the above (1) to (3) based on FIG. 6, the conversion coefficient ka corresponding to the no-load time Tx ′ is determined (step n104).

  Next, the value of the cell memory stored in the memory MR is read, and a plurality of average value operation elements 1 / q, 1 / (q + 1),. q + r ') ..., 1 / (q + r) is calculated as an average value, and is set as Wa. From the above equation (1), the zero point weight value Wn = Wnz which is the weight value at no load of the measuring conveyor 7 Are determined (step n105).

At this time, when the no-load time Tx ′ is less than the first no-load time Ta, the filter output can not be obtained, and the zero weight value can not be obtained (Wnz = 0). Also, assuming that the no-load time Tx ′ corresponds to the average value calculation element 1 / (q + r ′),
Wnz = 0 when Tx <<Ta
When Tx '≧ Ta, Wa = I (r') / (q + r ')
It becomes.

Next, using the determined conversion coefficient ka, the zero adjustment amount Wnza is
It is calculated by Wnza = ka · Wnz (step n106).

Next, Wz + Wnza → Wz is added to the value Wz of the integration variation register to perform zero adjustment.

As described above, according to the present embodiment, it is possible to obtain the zero weight value obtained without using another zero weight value obtained at no load time other than the no load time at which the zero weight value is obtained. When the zero point adjustment start flag Fz is set to "1", that is, as soon as the zero point weight value is measured, the zero point adjustment amount is corrected according to the reliability thereof, and the zero point adjustment amount is used. Since adjustment is performed, each time a zero weight value is acquired, it is possible to perform zero adjustment in accordance with the present zero fluctuation amount of the measuring conveyor 7 and in accordance with the reliability thereof.

  As a result, it is not necessary to acquire the zero weight value over a plurality of times and calculate the average value of the plurality of zero weight values as in the conventional example, and the unloaded condition of the weighing conveyor only rarely occurs. In such a transport line, the time interval at which the zero weight value can be acquired becomes long, and the zero fluctuates during that time, and multiple zeros including the old zero weight value acquired in the past and the latest zero weight value Since the zero value adjustment is performed by calculating the average value by the weight value, the calculated average value does not represent the latest zero weight value, and accurate zero adjustment can not be performed.

  Furthermore, since the output of the filter of the response characteristic according to the unloading time of the weighing conveyor 7 is selected to obtain the zero weight value, the conveyance interval between the preceding article and the succeeding article fluctuates, and the weighing conveyor 7 is not Even if the no-load time to be loaded fluctuates, it is possible to obtain the zero point weight value from the load signal appropriately filtered by the filter of the response characteristic according to the no-load time.

  By this, for example, the response characteristic of the filter is too slow compared to the unloading time of the weighing conveyor 7, and the load signal component measured when the article is still present on the weighing conveyor 7 is filtered and accurate. However, the response characteristic of the filter is too fast compared to the unloading time of the weighing conveyor 7 and the amplitude of the transient response vibration signal can not be obtained even though the unloading time is long. It can not be said that sufficient damping can not be achieved and stable zero weight values can not be obtained.

  In the above embodiment, although the zero point weight value is corrected by the conversion coefficient ka to make the zero point adjustment amount, as another embodiment of the present invention, for example, a size according to the length of no load time Tx ′ of the measuring conveyor 7 Saturation zero value adjustment saturation value is set, and zero point weight value (zero point fluctuation amount) measured at no load of the measuring conveyor 7 at the time of operation, no load time Tx 'of the measuring conveyor 7 measured at that time If the measured zero weight value is greater than or equal to the saturation value, the saturation value is used as the zero adjustment amount, and if less than the saturation value, the zero weight adjustment is performed using the measured zero weight value. May be performed.

  FIG. 9 shows an example in which the saturation zero adjustment amount, which is the saturation value of the zero adjustment amount, is determined stepwise in accordance with the no-load time Tx 'of the measuring conveyor 7, the saturation zero adjustment of the vertical axis The amount corresponds to an A / D count value obtained by filtering the output of the A / D converter 16.

  The saturated zero adjustment amount regulates the absolute value of the zero adjustment amount when correcting the zero weight value and calculating the zero adjustment amount, and according to the length of the no-load time Tx ′ of the weighing conveyor 7 The absolute value of the zero adjustment amount is regulated stepwise.

  As shown in FIG. 9, a plurality of boundary values T1 to T4 of no-load time Tx 'are defined between the first no-load time Ta and the second no-load time Tb, and a plurality of sections (1) to While classifying into (7), the saturation zero adjustment amount is determined for each of the sections (1) to (7).

  Here, in Wn = K. (Wa-Wi) -Wz of the above equation (1), the weight value Wn can be obtained based on the output Wa of the A / D converter 16. The digital resolution level is high, and the A / D count values Wa and Wn are configured to have a resolution higher than that of the display weight value actually displayed, for example, four times or more.

In the case where Wa and Wn have a resolution four times the display weight value, and the minimum display amount of the display weight value is wd, wd is an A / D count value Wn, and the count value is 4 and 0 .5 wd is a count value of 2 for Wn. The saturation zero adjustment amount is an absolute value, and the sign is the same as the sign of the measured zero weight value. In each section (1) to (7) of no-load time Tx 'of the measuring conveyor 7, the zero point adjustment amount is as follows.
(1) When Tx '<Ta Zero adjustment amount = 0
That is, zero adjustment is not performed.
(2) When Ta ≦ Tx ′ <T1 Saturation zero adjustment amount = 0.5 wd = 2 counts.

If the measured zero weight value is 2 counts or more, the zero adjustment amount is set to 2 (as the code is measured) and if less than 2 counts (one of 1 to 0), the measured zero weight value is taken as the zero adjustment amount. Do.
(3) When T1 ≦ Tx ′ <T2 Saturation zero adjustment amount = wd = 4 counts.

If the measured zero weight value is 4 counts or more, the zero adjustment amount is set to 4 (as the sign is measured) and if less than 4 counts (any of 3 to 0), the measured zero weight value is taken as the zero adjustment amount. Do.
(4) When T2 ≦ Tx ′ <T3 The saturation zero point adjustment amount = 1.5 wd = 6 counts.

If the measured zero weight value is 6 counts or more, zero adjustment amount = 6 (as indicated by the code), and if less than 6 counts (any of 5 to 0), the measured zero weight value is taken as the zero adjustment amount. Do.
(5) When T3 ≦ Tx ′ <T4 Saturation zero adjustment amount = 2.0 wd = 8 counts.

If the measured zero weight value is 8 counts or more, the zero adjustment amount is set to 8 (the code is as measured) and if less than 8 counts (any of 7 to 0), the measured zero weight value is taken as the zero adjustment amount. Do.
(6) When T4 ≦ Tx ′ <Tb Saturation zero adjustment amount = 2.5 wd = 10 counts.

If the measured zero weight value is 10 counts or more, the zero adjustment amount is set to 10 (as the sign is measured) and less than 10 counts (any of 9 to 0), the measured zero weight value is taken as the zero adjustment amount. Do.
(7) When Tx '≧ Tb The saturation zero point adjustment amount is not provided, and the measured zero point weight value is used as the zero point adjustment amount as it is.

  Next, a filter processing means suitable for FIG. 9 for determining the saturation value and obtaining the zero point adjustment amount will be described based on FIGS.

  The filters Fa, F1 to F4 and Fb in the filter processing means shown in FIG. 10A are filters of such a nature that the response characteristic is delayed in this order. The filter constant, order, and format of each filter are set such that the response time of each filter Fa, F1 to F4 and Fb has a value corresponding to the length of the no-load time Tx 'of the measuring conveyor 7.

Let the outputs of the filters Fa, F1 to F4, Fb be fa, f1, f2, f3, f4, fb, and the zero weight values obtained from those outputs be Waa, Wa1, Wa2, Wa3, Wa4, Wa4, Wab, respectively. .
In the filter Fa, for example, the time required for the output to respond to “O. 999” (= response time) for the input of the step signal of “1” is the first no load time Ta. It has response characteristics. The output fa is selected when the no-load time Tx ′ is in the section (1) or the section (2) of FIG. 9 described above, and the zero point weight value Waa is determined by the output fa. However, when the no-load time Tx ′ of the measuring conveyor 7 is section (1), it is not necessary to obtain the zero point weight value, and the zero point adjustment amount is forcibly set to 0 as described above.

  The filter F1 has the response time T1 in FIG. 9 and the output f1 is selected when the no-load time Tx 'is in section (3).

  In the filter F2, the response time is T2 in FIG. 9, and the output f2 is selected when the no-load time Tx 'is an interval (4).

  In the filter F3, the response time is T3 in FIG. 9, and the output f3 is selected when the no-load time Tx 'is an interval (5).

  The filter F4 has the response time T4 in FIG. 9 and the output f4 is selected when the no-load time Tx 'is a section (6).

  In the filter Fb, the response time is the second no-load time Tb, and the output fb is selected when the no-load time Tx 'is a section (7).

  The filter processing means of FIG. 10 (b) is composed of a filter row in which filters Fa, F1 ', F2', F3 ', F4', and Fb 'are cascade-connected.

  The response of the output f1 of the dependent filter of the filter Fa and the filter F1 'is the same as that of the filter F1 of FIG. 10A, the dependent filter of the filter Fa, the filter F1' and the filter F2 ' The response time of the output f3 of the dependent filter of the filter Fa, the filter F1 ', the filter F2' and the filter F3 'so that the response time of the output f2 is the same as the filter F2 of FIG. 10, the response time of the output f4 of the dependent filter of the filter Fa, the filter F1 ', the filter F2', the filter F3 'and the filter F4' is the same as the filter F3 of FIG. Dependent filters of the filter Fa, the filter F1 ', the filter F2', the filter F3 ', the filter F4', and the filter Fb 'so as to be the same as the filter F4 of (a) The characteristics of the filters Fa, F1 ', F2', F3 ', F4' and Fb 'are determined so that the response time of the output fb is the same as the filter Fb of FIG. 10A. .

  The filters Fa, F1 ', F2', F3 ', F4', and Fb 'are selected according to the response time to determine the zero point weight value as in the above embodiment.

  In the above embodiment, as shown in FIG. 6, the conversion coefficient ka is defined as a linear function of the unloading time Tx ′ of the measuring conveyor 7, but may be defined by another function.

  As described above, let Tx be the time interval between articles, and the first no-load time Ta which is the shortest measurable time of the zero weight value at which the zero adjustment can be performed, for example, Ta = 100 (msec), and Tx 'be Tx'. The no-load time of the measuring conveyor 7, tp is a no-load start time, and the second no-load time Tb capable of measuring a sufficiently stable zero point weight value is Tb = tp. Furthermore, no-load time Tc is Ta <Tc <Tb Choose to

  The timing of this no-load time Tc is assumed to be the timing corresponding to the addition value I (r ') corresponding to the average value calculation element 1 / (q + r') in FIG.

  The timing of no-load time Tx ′ = Ta is a timing corresponding to the addition value I (0) corresponding to the average value calculation element 1 / q in FIG.

  In advance, the article is repeatedly flowed in the adjustment stage, and the values of the added values I (0) and I (r ') corresponding to the filter output in the no-load time Tx' = Ta, Tc are respectively measured and stored in the memory, n If an operation command is issued after three trials, the average value I (0) / q of the added value I (0) in FIG. 5 and the average of the added value I (r ') 迄 in the no-load time Tx' = Ta. Calculate the value I (r ') / (q + r'). The filter output I (0) / q corresponding to no-load time Tx '= Ta at the end of the test and the filter output I (r') / (q + r ') corresponding to no-load time Tx' = Tc Standard deviations σa and σc are determined from the values of the cycles.

From these values, an equation for obtaining an estimated value of the standard deviation σ (Tx ′) at any load time Tx ′ is given by
σ ( ^Tx ′) = B · A ⁽ Tx′−Ta ^{) Tx} ′ ≧ Ta (2)
The values of A and B in the equation (2) are determined from the no-load time Tx ′ and the standard deviations σa and σc.

However, in the case of Tx ′ <Ta, it is defined that σ (Tx ′) = B. (As the zero adjustment amount = 0)
As the no-load time Tx 'increases, the amount of variation of the zero point weight measurement value decreases and stabilizes to a certain value, so the time function σ (Tx') of the standard deviation gradually converges to a certain value C smaller than B. Therefore, it is determined that A <1.

  As an equation for obtaining the zero adjustment amount Wnza from the zero weight measurement value Wnz in the no-load time Tx ', the following equation is applied as described above.

Wnza = ka · Wnz (3)
Assuming that ka is a conversion coefficient corresponding to the zero point weight measurement value, k = for equation (2) in order to determine the conversion coefficient ka when the no-load time Tx ′ of the measuring conveyor 7 is measured during operation. σ (Tx ′) / B (4)
ka = 1-k (5)
Define a formula

That is, when the measurement timing of the zero weight value is ^Tx ′ = Ta, A ⁽ Tx′−Ta ⁾ = 1
Therefore, according to the above equation (2), σ (Tx ′) = σ (Ta) = B
Therefore, according to the equation (4), k = σ (Ta) / B = 1
Also, from the above equation (5), ka = 0
It is.
Also,
In the case of Tx ′> Ta, since σ (Tx ′) <σ (Ta) = B is obtained, the value of k is
k = σ (Tx ') / B <1
∴ 1> ka 0 0
The value closer to 1 is obtained as the no-load time Tx ′ is larger.

  That is, since the zero adjustment amount Wnza is determined to a value closer to the zero weight measurement value Wnz as the no load time Tx 'is longer, the zero adjustment amount Wnza is closer to the zero weight measurement value Wnz as the no load time Tx' is longer. It becomes a value.

  Equation (2) is determined by the item weighing trial test at the adjustment stage. Further, equations (4) and (5) are prepared in advance.

  The operation procedure is as follows.

  The no-load time Tx ′ of the measuring conveyor 7 is measured as Tx ′ = Tx−tp.

  The value of Tx 'is put into equation (2) to find σ (Tx').

  From the obtained σ (Tx ′), the conversion coefficient ka is calculated from the equations (4) and (5).

  The zero point weight value at the no load time Tx 'is measured.

When Tx ′ = Tx−tp <Ta, it is defined that σ (Tx ′) = B. (Set ka to 0)
At that time, since there is a limit to the number of cell memories that are subordinate columns of the shift register in the filter, which are prepared to measure zero weight values, the memory for obtaining the I (r) output in FIG. , No load time Tx ',
Tx '= Tb = {(N1-1) + (N2-1) + (q + r-1)}. DELTA.t
When it is the above, it is assumed that the measured value of the zero weight value is always calculated by I (r) / (q + r).

  The zero adjustment amount is determined from the equation (3) according to the determined conversion coefficient ka, and the zero adjustment is performed.

  In each of the above embodiments, although the degree of correction when calculating the zero adjustment amount by correcting the measured zero weight value is made different according to the no-load time Tx ′ of the measuring conveyor 7, the other embodiments of the present invention As an embodiment, for example, even if the weighing conveyor 7 may be in a no-load state, in most cases, in a transport line or the like where the no-load time is short, the zero weight value is uniformly applied regardless of the no-load time Tx '. It may be reduced.

  In this case, when the zero weight value is measured, the zero weight value is uniformly reduced regardless of the length of the no-load time Tx ′ to obtain the zero adjustment amount.

  For example, one conversion coefficient ka (≦ 1) is set by operating the input unit 18 as setting means, and the zero point adjustment value is calculated by multiplying the zero weight value constantly measured by the set conversion coefficient ka. Do.

  Alternatively, when the zero weight value is measured, the zero adjustment amount is uniformly limited to the saturation zero adjustment amount regardless of the length of the no-load time Tx ′.

  For example, one saturation zero adjustment amount is set by operating the input unit 18, and when the measured zero weight value is equal to or more than the set saturation zero adjustment amount, the saturation zero adjustment amount is set as the zero adjustment amount. When the measured zero weight value is less than the saturation zero adjustment amount, the zero weight adjustment may be performed as the zero adjustment amount as it is.

In order to measure the zero point weight value, it is necessary to detect that the weighing conveyor 7 is in the unloaded state, but in the measurement of the time interval Tx between the articles, as in the above embodiment, the unloaded time Tx 'To Tx' = Tx-tp> 0
If the above condition is satisfied, it can be known that the unloaded condition of the weighing conveyor 7 has occurred, that is, the unloaded condition of the weighing conveyor 7 can be detected.

  Further, in the same manner as in FIG. 7 of the above-described embodiment, the zero load value may be measured on the assumption that the no load time is ended by the subsequent article being detected by the article sensor 12. In this case, no load time needs to be used.

  In the above embodiment, a photosensor including a light emitting element and a light receiving element is installed as the article sensor 12 between the infeed conveyor 6 and the weighing conveyor 7, and the tip of the leading article to be conveyed is the light of the photosensor. , And it is assumed that the article has reached the entrance of the weighing conveyor 7, and from this timing, counting of time starts and the time until the tip of the following article blocks the light of the photosensor, ie, the time between articles Although the interval is measured, as another embodiment of the present invention, for example, a method of monitoring the transport condition of the article on the measuring conveyor 7 by an imaging device, or detecting the level of the load signal to measure the time interval of the article You may do so.

  In the above embodiment, in order to measure the zero weight value, the load signal for measuring the zero weight is filtered by the filtering means having a plurality of filters having various response characteristics. As an embodiment of the present invention, the load signal for measuring the zero weight may be filtered by one type of filter. Also in this case, it is sufficient to wait until the final timing of the no-load time to obtain the zero point weight value.

DESCRIPTION OF SYMBOLS 1 Filling apparatus 2 Packaging apparatus 3 Merchandise production apparatus 4 Weight sorting machine 5 Conveying conveyor 6 Infeed conveyor 7 Weighing conveyor 8 Delivery conveyor 10 Load sensor 11 Control device 12 Article sensor 20 Filter processing means G Article

Claims (5)

A transport measuring device provided in a transport line for transporting articles and transporting the articles, wherein the transport weighing apparatus weighs the articles while transporting the articles by the weighing conveyor,
No-load state detection means for detecting a no-load state in which no item is present on the weighing conveyor;
Zero point weight value acquiring means for acquiring a zero point weight value which is a weight value of the weighing conveyor in the unloading time in which the weighing conveyor is in the unloaded state;
Wherein a zero weight value obtained by the zero-point weight value obtaining means, and correct without the use of other zero weight values obtained in another unloading time is the no-load time of the zero-point weight value is obtained Zero adjustment amount calculating means for calculating the zero adjustment amount;
Zero point adjustment means for performing zero point adjustment of the weighing conveyor according to the zero point adjustment amount calculated by the zero point adjustment amount calculation means;
Transport metering device. The non-load time measuring means for measuring the time during which the weighing conveyor is in the non-load state as the non-load time;
The zero point weight value acquiring means acquires the zero point weight value at a time point corresponding to the no-load time,
The zero point adjustment amount calculating means calculates the zero point adjustment amount by correcting the zero point weight value according to the no-load time.
The transport weighing device according to claim 1. The zero adjustment amount calculating means corrects the zero adjustment amount on the basis of a conversion coefficient for converting the zero weight value into the zero adjustment amount.
The conversion coefficient is determined so as to convert the zero point weight value into a zero point adjustment amount whose absolute value is smaller than the zero point weight value as the no-load time is shorter.
The transport weighing device according to claim 2. The zero point adjustment amount calculating means calculates the zero point adjustment amount by correcting the zero point weight value based on a saturation zero point adjustment amount which regulates an absolute value of the zero point adjustment amount according to the no-load time. Yes,
The saturation zero adjustment amount is determined so as to regulate the absolute value smaller than the zero weight value as the no-load time is shorter.
The transport weighing device according to claim 2. Setting means operated to set the conversion factor or the saturation zero adjustment amount,
The conveyance weighing device according to claim 3 or 4.

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